<?phpClass DB {     private $link_id;    private $handle;    private $is_log;    private $time;     //构造函数    public function __construct() {        $this->time = $this->microtime_float();        require_once("config.db.php");        $this->connect($db_config["hostname"], $db_config["username"], $db_config["password"], $db_config["database"], $db_config["pconnect"]);        $this->is_log = $db_config["log"];        if($this->is_log){            $handle = fopen($db_config["logfilepath"]."dblog.txt", "a+");            $this->handle=$handle;        }    }         //数据库连接    public function connect($dbhost, $dbuser, $dbpw, $dbname, $pconnect = 0,$charset=‘utf8‘) {        if( $pconnect==0 ) {            $this->link_id = @mysql_connect($dbhost, $dbuser, $dbpw, true);            if(!$this->link_id){                $this->halt("数据库连接失败");            }        } else {            $this->link_id = @mysql_pconnect($dbhost, $dbuser, $dbpw);            if(!$this->link_id){                $this->halt("数据库持久连接失败");            }        }        if(!@mysql_select_db($dbname,$this->link_id)) {            $this->halt(‘数据库选择失败‘);        }        @mysql_query("set names ".$charset);    }         //查询     public function query($sql) {        $this->write_log("查询 ".$sql);        $query = mysql_query($sql,$this->link_id);        if(!$query) $this->halt(‘Query Error: ‘ . $sql);        return $query;    }         //获取一条记录（MYSQL_ASSOC，MYSQL_NUM，MYSQL_BOTH）                  public function get_one($sql,$result_type = MYSQL_ASSOC) {        $query = $this->query($sql);        $rt =& mysql_fetch_array($query,$result_type);        $this->write_log("获取一条记录 ".$sql);        return $rt;    }     //获取全部记录    public function get_all($sql,$result_type = MYSQL_ASSOC) {        $query = $this->query($sql);        $i = 0;        $rt = array();        while($row =& mysql_fetch_array($query,$result_type)) {            $rt[$i]=$row;            $i++;        }        $this->write_log("获取全部记录 ".$sql);        return $rt;    }         //插入    public function insert($table,$dataArray) {        $field = "";        $value = "";        if( !is_array($dataArray) || count($dataArray)<=0) {            $this->halt(‘没有要插入的数据‘);            return false;        }        while(list($key,$val)=each($dataArray)) {            $field .="$key,";            $value .="‘$val‘,";        }        $field = substr( $field,0,-1);        $value = substr( $value,0,-1);        $sql = "insert into $table($field) values($value)";        $this->write_log("插入 ".$sql);        if(!$this->query($sql)) return false;        return true;    }     //更新    public function update( $table,$dataArray,$condition="") {        if( !is_array($dataArray) || count($dataArray)<=0) {            $this->halt(‘没有要更新的数据‘);            return false;        }        $value = "";        while( list($key,$val) = each($dataArray))        $value .= "$key = ‘$val‘,";        $value .= substr( $value,0,-1);        $sql = "update $table set $value where 1=1 and $condition";        $this->write_log("更新 ".$sql);        if(!$this->query($sql)) return false;        return true;    }     //删除    public function delete( $table,$condition="") {        if( empty($condition) ) {            $this->halt(‘没有设置删除的条件‘);            return false;        }        $sql = "delete from $table where 1=1 and $condition";        $this->write_log("删除 ".$sql);        if(!$this->query($sql)) return false;        return true;    }     //返回结果集    public function fetch_array($query, $result_type = MYSQL_ASSOC){        $this->write_log("返回结果集");        return mysql_fetch_array($query, $result_type);    }     //获取记录条数    public function num_rows($results) {        if(!is_bool($results)) {            $num = mysql_num_rows($results);            $this->write_log("获取的记录条数为".$num);            return $num;        } else {            return 0;        }    }     //释放结果集    public function free_result() {        $void = func_get_args();        foreach($void as $query) {            if(is_resource($query) && get_resource_type($query) === ‘mysql result‘) {                return mysql_free_result($query);            }        }        $this->write_log("释放结果集");    }     //获取最后插入的id    public function insert_id() {        $id = mysql_insert_id($this->link_id);        $this->write_log("最后插入的id为".$id);        return $id;    }     //关闭数据库连接    protected function close() {        $this->write_log("已关闭数据库连接");        return @mysql_close($this->link_id);    }     //错误提示    private function halt($msg=‘‘) {        $msg .= "\r\n".mysql_error();        $this->write_log($msg);        die($msg);    }     //析构函数    public function __destruct() {        $this->free_result();        $use_time = ($this-> microtime_float())-($this->time);        $this->write_log("完成整个查询任务,所用时间为".$use_time);        if($this->is_log){            fclose($this->handle);        }    }         //写入日志文件    public function write_log($msg=‘‘){        if($this->is_log){            $text = date("Y-m-d H:i:s")." ".$msg."\r\n";            fwrite($this->handle,$text);        }    }         //获取毫秒数    public function microtime_float() {        list($usec, $sec) = explode(" ", microtime());        return ((float)$usec + (float)$sec);    }} ?>

<?php     $db_config["hostname"] = "localhost"; //服务器地址    $db_config["username"] = "root"; //数据库用户名    $db_config["password"] = "123"; //数据库密码    $db_config["database"] = "test"; //数据库名称    $db_config["charset"] = "utf8";//数据库编码    $db_config["pconnect"] = 1;//开启持久连接    $db_config["log"] = 1;//开启日志    $db_config["logfilepath"] = ‘./‘;//开启日志?>